Sabot launched projectiles have been used in artillery for over two hundred years. The use of a sabot allows projectiles to be launched from a gun barrel. Once used, the sabot is discarded and subsequently destroyed as soon as it exits the gun barrel, at which time its function is over and the sabot launched projectile is released to continue on its trajectory.
Pressure wave generators can be used to create pressure waves that may be used to compress a medium, transfer part of the pressure wave energy to that medium, generate energy in the medium due to concentration of the pressure wave energy, and/or initiate chemical reactions or physical changes in the medium. The medium may be a solid, liquid, gas, and/or plasma.
Various methods can be used for launching a pressure wave in a medium, such as applying direct mechanical impact on the surface coupled to the medium, detonation, explosions, electrical sparks, intense radiation beams, oscillating and amplifying mechanisms, etc.
Examples of pressure wave generators are described in the commonly owned U.S. Patent Application Publication No. 2010/0163130 and International Patent Application (PCT) Publication No. WO 2012/113057, which are incorporated by reference herein in their entirety. These two publications describe examples of a pressure wave generator for generating a pressure wave (or a plurality of pressure waves) in a medium. Any of the example pressure wave generators, components of the generators, or methods for operating generators described in any of these publications can be used with the embodiments of pressure wave generation apparatus and methods described herein. The pressure wave can be used to compress the medium and increase its temperature, pressure, energy, and/or density. The pressure wave can be generated by a mechanical impact of an accelerated piston on a transducer coupled to the medium. The transducer can at least partially convert kinetic energy of the movable piston into a pressure wave in the medium.
The piston in a pressure wave generator can be made from heat treated steel with features machined into it for bearing rings, seals, a control rod, control rod attachments and other devices. These features can be complex to produce, can disturb uniformity of the piston, and can introduce stress concentrations in corners and cavities leading to premature failure in use of the piston. They can also complicate the heat treatment of the piston, which may lead to failure of the piston, e.g. thermal cracking of the piston.